Magnesium deficiency enhances oxidative stress and collagen synthesis in vivo in the aorta of rats.
Magnesium deficiency has been shown to produce vascular lesions in experimental animals, but the underlying mechanisms of vascular injury are not clear. It has been reported that in rodents, magnesium deficiency enhances circulating levels of factors that promote free radical generation and are mitogenic. In pursuance of these observations, the present study tested the hypothesis that magnesium deficiency may enhance oxidative stress and trigger an accelerated growth response in vivo in the aorta of rats. Oxidative stress was evaluated in terms of levels of thiobarbituric acid-reactive substances in the serum and aorta and activity of superoxide dismutase and catalase in the aorta; fractional rates of collagen synthesis were assessed using [3H]-proline. Serum and tissue levels of magnesium and calcium were determined by atomic absorption spectrophotometry. The present study demonstrated for the first time that magnesium deficiency significantly (P < 0.001) increases levels of thiobarbituric acid-reactive substances in the aorta of rats. Other changes in the aorta of animals on the Mg-deficient diet included a significant reduction (54%, P < 0.001) in the activity of superoxide dismutase and catalase (37%, P < 0.01) and a 19% increase in net fractional rates of collagen synthesis (P < 0.05). While serum magnesium was significantly reduced in these animals (P < 0.001), aortic tissue levels of magnesium in these animals remained unaltered throughout the duration of the study, suggesting the existence of other control mechanisms, apart from reduced tissue levels of magnesium, mediating the observed effects. These findings suggest that magnesium deficiency may trigger a wound healing response, involving oxidative injury and growth stimulation, in the vascular system.
Shivakumar
K
K
Division of Cellular and Molecular Cardiology, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, India.
Kumar
B P
BP
D000818:Animals; D003094:Collagen / Q000096:biosynthesis*; D005260:Female; D015227:Lipid Peroxidation / Q000502:physiology; D008275:Magnesium Deficiency / Q000503:physiopathology*; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism
D003094:Collagen; D013482:Superoxide Dismutase